Method and apparatus for antenna tuning and transmit path selection

Abstract

Certain aspects of the present disclosure propose a method and an apparatus for antenna tuning and transmit path selection in an RF system. A method may include antenna diversity path selection by (optionally) diagnosing damaged antennas, tuning antennas, and selecting an antenna with better performance. Embodiments can be used in wireless radio-frequency (RF) front-ends. Other aspects, embodiments, and features are also claimed and described.

We claim: 
     
       1. A method for antenna selection at a wireless communications device, the comprising:
 detecting antenna conditions for first and second antennas; 
 tuning the first and the second antennas, based on the detected antenna conditions, to reduce impedance mismatch in their respective radio frequency (RF) chain; 
 detecting whether one or more of the first and second antennas are damaged based on the detected antenna conditions, wherein the tuning of at least one of the first and second antennas is terminated early when one or more of the first and second antennas are determined to be damaged; and 
 selecting at least one of the first antenna or the second antenna for at least one of transmission or reception, based on an evaluation of the antenna conditions after the tuning. 
 
     
     
       2. The method of  claim 1 , wherein the selecting comprises: selecting either the first antenna or the second antenna for transmission based on the evaluation. 
     
     
       3. The method of  claim 1 , wherein the selecting comprises: selecting neither, one, or both of the first and second antennas for reception, based on the evaluation. 
     
     
       4. The method of  claim 1 , wherein the selecting comprises:
 selecting the first antenna when the second antenna is damaged; or selecting the second antenna when the first antenna is damaged, wherein a damaged antenna has a measured performance below a predetermined threshold. 
 
     
     
       5. The method of  claim 1 , comprising: switching off a receive antenna path for at least one of the first or second antennas when performance of at least one of the first or the second antennas is below a certain threshold. 
     
     
       6. The method of  claim 1 , wherein detecting antenna conditions comprises:
 measuring transmit power loss through the first and the second antennas. 
 
     
     
       7. The method of  claim 1 , wherein the tuning comprises: performing a closed-loop algorithm, wherein tuning is iteratively adjusted based on obtained antenna performance information. 
     
     
       8. The method of  claim 1 , further comprising: detecting antenna conditions of the first and the second antennas after tuning. 
     
     
       9. The method of  claim 7 , wherein the obtained antenna performance information comprises at least one of information received from a base station and detected transmit power loss. 
     
     
       10. An apparatus for wireless communications, comprising:
 means for detecting antenna conditions indicative of impedance mismatch for first and second antennas; 
 means for tuning the first and the second antennas, based on the detected antenna conditions, to reduce impedance mismatch in their respective radio frequency (RF) chain; 
 means for detecting whether one or more of the first and second antennas are damaged based on the detected antenna conditions, wherein the tuning of at least one of the first and second antennas is terminated early when one or more of the first and second antennas are determined to be damaged; 
 means for evaluating the antenna conditions after the tuning; and 
 means for selecting at least one of the first antenna or the second antenna for at least one of transmission or reception, based on the evaluation of the antenna conditions after the tuning. 
 
     
     
       11. The apparatus of  claim 10 , wherein the means for selecting selects either the first antenna or the second antenna for transmission based on the evaluation. 
     
     
       12. The apparatus of  claim 10 , wherein the means for selecting selects neither, one, or both of the first and second antennas for reception based on the evaluation. 
     
     
       13. The apparatus of  claim 10 , wherein the means for selecting: selects the first antenna when the second antenna is damaged; or selects the second antenna when the first antenna is damaged, wherein a damaged antenna has a measured performance below a predetermined threshold. 
     
     
       14. The apparatus of  claim 10 , further comprising a means for switching off a receive antenna path for at least one of the first or second antennas when performance of at least one of the first or the second antennas is below a certain threshold. 
     
     
       15. The apparatus of  claim 10 , wherein the means for detecting measures transmit power loss through the first and the second antennas. 
     
     
       16. The apparatus of  claim 10 , wherein the means for tuning performs a closed-loop algorithm, wherein tuning is iteratively adjusted based on obtained antenna performance information. 
     
     
       17. The apparatus of  claim 10 , further comprising: detecting antenna conditions of the first and the second antennas after tuning. 
     
     
       18. An apparatus for wireless communications comprising:
 a communication interface; and 
 at least one processor configured to:
 detect antenna conditions indicative of impedance mismatch for first and second antennas; 
 tune the first and the second antennas, based on the detected antenna conditions, to reduce impedance mismatch in their respective radio frequency (RF) chain; 
 detect whether one or more of the first and second antennas are damaged based on the detected antenna conditions, wherein the tuning of at least one of the first and second antennas is terminated early when one or more of the first and second antennas are determined to be damaged; and 
 evaluate the antenna conditions after the tuning; and 
 select at least one of the first antenna or the second antenna for at least one of transmission or reception, based on the evaluation of the antenna conditions after the tuning. 
 
 
     
     
       19. The apparatus of  claim 18 , wherein the processor is configured to select either the first antenna or the second antenna for transmission based on the evaluation. 
     
     
       20. The apparatus of  claim 18 , wherein the processor is configured to select neither, one, or both of the first and second antennas for reception, based on the evaluation. 
     
     
       21. The apparatus of  claim 18 , wherein the processor is configured to select the first antenna when the second antenna is damaged; or selecting the second antenna when the first antenna is damaged, wherein a damaged antenna has a measured performance below a predetermined threshold. 
     
     
       22. The apparatus of  claim 18 , wherein the processor is configured to switch off a receive antenna path for at least one of the first or second antennas when performance of at least one of the first or the second antennas is below a certain threshold. 
     
     
       23. The apparatus of  claim 18 , wherein the processor is configured to obtain measurements measuring transmit power loss through the first and the second antennas. 
     
     
       24. The method of  claim 18 , wherein the processor is configured to instruct a tuner to perform a closed-loop algorithm, wherein tuning is iteratively adjusted based on obtained antenna performance information. 
     
     
       25. A computer program product comprising a non-transitory computer readable medium having instructions stored thereon, the instructions executable by one or more processors for:
 detecting antenna conditions indicative of impedance mismatch for first and second antennas; 
 tuning the first and the second antennas, based on the detected antenna conditions, to reduce impedance mismatch in their respective radio frequency (RF) chain; 
 detecting whether one or more of the first and second antennas are damaged based on the detected antenna conditions, wherein the tuning of at least one of the first and second antennas is terminated early when one or more of the first and second antennas are determined to be damaged; and 
 evaluating the antenna conditions after the tuning; and 
 selecting at least one of the first antenna or the second antenna for at least one of transmission or reception, based on the evaluation of the antenna conditions after the tuning. 
 
     
     
       26. A user equipment (UE), comprising:
 a plurality of antennas comprising at least first and second antennas; 
 detection circuitry for detecting antenna conditions indicative of impedance mismatch for the first and second antennas; 
 tuning circuitry for tuning the first and the second antennas, based on the detected antenna conditions, to reduce impedance mismatch in their respective radio frequency (RF) chain; 
 circuitry for detecting whether one or more of the first and second antennas are damaged based on the detected antenna conditions, wherein the tuning of at least one of the first and second antennas is terminated early when one or more of the first and second antennas are determined to be damaged; and 
 a cross-switch configured to selectively include at least one of the first or second antennas in at least one of a transmission path or a diversity receive path; and 
 at least one processor configured to evaluate antenna conditions after the tuning, and configured to select, via the cross-switch, at least one of the first antenna or the second antenna for at least one of transmission via the transmission path or reception via the diversity receive path, based on the evaluation of the antenna conditions after the tuning. 
 
     
     
       27. The UE of  claim 26 , wherein the cross switch is configured to select neither, one, or both of the first and second antennas for reception, based on the evaluation. 
     
     
       28. The UE of  claim 26 , wherein the cross switch is configured to select the first antenna when the second antenna is damaged; or select the second antenna when the first antenna is damaged, wherein a damaged antenna has a measured performance below a predetermined threshold. 
     
     
       29. The UE of  claim 26 , wherein the cross switch is configured to switch off a receive antenna path for at least one of the first or second antennas when performance of at least one of the first or the second antennas is below a certain threshold. 
     
     
       30. The UE of  claim 26 , wherein the tuning circuitry is configured to perform a closed-loop algorithm, wherein tuning is iteratively adjusted based on obtained antenna performance information.